Walking tall to protect the species
December 12, 2007The transition from apes to humans may have been partially triggered by the need to stand on two legs, in order to safely carry heavier babies. This theory of species evolution presented by Lia Amaral from the University of São Paulo in Brazil has just been published online in Springer’s journal, Naturwissenschaften.
For safety, all nonhuman primates carry their young clinging to their fur from birth, and species survival depends on it. The carrying pattern changes as the infant grows. Newborns are carried clinging to their mother’s stomach, often with additional support. Months later, infants are carried over the adult body usually on the mother’s back, and this carrying pattern lasts for years in apes. However, this necessity to carry infants safely imposes limits on the weight of the infants.
Through a detailed mechanical analysis of how different types of apes - gibbons, orangutans and gorillas - carry their young, looking at the properties of ape hair, infant grip, adult hair density and carrying position, Amaral demonstrates a relationship between infant weight, hair friction and body angle which ensures ape infants are carried safely.
Amaral also shows how the usual pattern of primate carrying of heavy infants is incompatible with bipedalism. African apes have to persist with knuckle-walking on all fours, or ‘quadruped’ position, in order to stop their young from slipping off their backs.
The author goes on to suggest that the fall in body hair in primates could have brought on bipedality as a necessary consequence, through the strong selective pressure of safe infant carrying, as infants were no longer able to cling to their mother’s body hairs. In the author’s opinion, safe carrying of heavy infants justified the emergence of the biped form of movement. Although an adult gorilla is much heavier than an adult human, its offspring is only half the weight of a human baby.
Amaral concludes that this evolution to bipedality has important consequences for the female of the species. Indeed, it frees the arms and hands of males and juveniles, but females have their arms and hands occupied with their young. This restriction of movement placed limits on food gathering for biped females carrying their infants, and may have been at the origin of group cooperation.
Source: Springer
-
Night, weekend delivery OK for babies with birth defects
Feb 10, 2012 |
not rated yet |
0
-
The heroes of India's quest to wipe out polio
Feb 08, 2012 |
not rated yet |
0
-
Domestic cats, and wild bobcats and pumas, living in same area have same diseases
Feb 06, 2012 |
1 / 5 (1) |
0
-
Anaphylactic shock after vaccination 'extremely rare'
Jan 24, 2012 |
5 / 5 (1) |
0
-
Stranded baby seals concern Dutch rescuers
Jan 23, 2012 |
5 / 5 (1) |
0
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (33) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (4) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (2) |
0
More news stories
A mitosis mystery solved: How chromosomes align perfectly in a dividing cell
Although the process of mitotic cell division has been studied intensely for more than 50 years, Whitehead Institute researchers have only now solved the mystery of how cells correctly align their chromosomes during symmetric ...
5 hours ago |
4.5 / 5 (8) |
0
|
Researchers find extensive RNA editing in human transcriptome
In a new study published online in Nature Biotechnology, researchers from BGI, the world's largest genomics organization, reported the evidence of extensive RNA editing in a human cell line by analysis of RNA-seq data, demons ...
5 hours ago |
5 / 5 (4) |
0
|
The proteins ensuring genome protection
Researchers from the University of Geneva (UNIGE), Switzerland, have discovered the crucial role of two proteins in developing a cell 'anti-enzyme shield'. This protection system, which operates at the level of molecular ...
5 hours ago |
5 / 5 (3) |
0
|
Entire genome of extinct human decoded from fossil
(PhysOrg.com) -- In 2010, Svante Pääbo and his colleagues presented a draft version of the genome from a small fragment of a human finger bone discovered in Denisova Cave in southern Siberia. The ...
Feb 07, 2012 |
4.7 / 5 (59) |
48
|
Why are there so few fish in the Earth's oceans?
(PhysOrg.com) -- A Stony Brook University researcher has found that, contrary to popular belief, there are not plenty of fish in the sea.
Feb 08, 2012 |
4.2 / 5 (18) |
27
|
Declining health-care productivity in England: Who says so?
Reports that the National Health Service in England has been declining in productivity in the last decade appear to have been accepted as fact. However, a Viewpoint published Online First by The Lancet disputes this. The Vi ...
Scientists discover molecular secrets of 2,000-year-old Chinese herbal remedy
For roughly two thousand years, Chinese herbalists have treated Malaria using a root extract, commonly known as Chang Shan, from a type of hydrangea that grows in Tibet and Nepal. More recent studies suggest that halofuginone, ...
New method to examine batteries -- MRI from the inside
There is an ever-increasing need for advanced batteries for portable electronics, such as phones, cameras, and music players, but also to power electric vehicles and to facilitate the distribution and storage of energy derived ...
Overeating may double risk of memory loss
New research suggests that consuming between 2,100 and 6,000 calories per day may double the risk of memory loss, or mild cognitive impairment (MCI), among people age 70 and older. The study was released today and will be ...
Lab study raises questions over nano-particle impact
Tests involving chickens have raised questions about the impact on health from engineered nano-particles, the ultra-fine grains commonly used in drugs and processed foods, scientists said on Sunday.
Starve a virus, feed a cure? Findings show how some cells protect themselves against HIV
A protein that protects some of our immune cells from the most common and virulent form of HIV works by starving the virus of the molecular building blocks that it needs to replicate, according to research published online ...